By focussing on the image in front of him and flying close to the seracs at a high speed, the pilot likely was unable to identify the impeding serac, assess its proximity, and alter the helicopter's course in time to avoid it. Based on the height and angle of the mark left on the serac by the main rotor and the height of the mark left by the helicopter when it collided with the ice wall, which were at relatively the same height, it is concluded that the helicopter was in powered flight when its main rotor first hit the serac. When the blade broke, the main rotor system would have become severely out of balance, and control would have been lost. Even with power, the pilot would not have been able to manoeuvre the helicopter to avoid the ice terrain ahead.Analysis By focussing on the image in front of him and flying close to the seracs at a high speed, the pilot likely was unable to identify the impeding serac, assess its proximity, and alter the helicopter's course in time to avoid it. Based on the height and angle of the mark left on the serac by the main rotor and the height of the mark left by the helicopter when it collided with the ice wall, which were at relatively the same height, it is concluded that the helicopter was in powered flight when its main rotor first hit the serac. When the blade broke, the main rotor system would have become severely out of balance, and control would have been lost. Even with power, the pilot would not have been able to manoeuvre the helicopter to avoid the ice terrain ahead. The pilot was operating the helicopter at a height and speed that left no room for error in dimensional judgement. The pilot lost control of the helicopter when the main rotor struck the ice and broke.Findings as to Causes and Contributing Factors The pilot was operating the helicopter at a height and speed that left no room for error in dimensional judgement. The pilot lost control of the helicopter when the main rotor struck the ice and broke. The pilot was certificated within the standards set for aerial work operations. No mechanical malfunction was reported on the aircraft, nor was anything learned during the investigation that would suggest mechanical malfunction.Other Findings The pilot was certificated within the standards set for aerial work operations. No mechanical malfunction was reported on the aircraft, nor was anything learned during the investigation that would suggest mechanical malfunction.